31-2
Catalyst 3750 SwitchSoftware Configuration Guide
OL-8550-09
Chapter31 Configuring System Message Logging
Configuring System Message Logging
You can set the severity level of the messages to control the type of messages displayed on the consoles
and each of the destinations. You can time-stamp log messages or set the syslog source address to
enhance real-time debugging and management. For information on possible messages, see the system
message guide for this release.
You can access logged system messages by using the switch command-line interface (CLI) or by saving
them to a properly configured syslog server. The switch software saves syslog messages in an internal
buffer on a standalone switch, and in the case of a switch stack, on the stack master. If a standalone
switch or the stack master fails, the log is lost unless you had saved it to flash memory.
You can remotely monitor system messages by viewing the logs on a syslog server or by accessing the
switch through Telnet or through the console port. In a switch stack, all stack member consoles provide
the same console output.
Configuring System Message Logging
These sections contain this configuration information:
•System Log Message Format, page 31-2
•Default System Message Logging Configuration, page31-4
•Disabling Message Logging, page31-4 (optional)
•Setting the Message Display Destination Device, page31-5 (optional)
•Synchronizing Log Messages, page 31-7 (optional)
•Enabling and Disabling Time Stamps on Log Messages, page31-8 (optional)
•Enabling and Disabling Sequence Numbers in Log Messages, page31-8 (optional)
•Defining the Message Severity Level, page31-9 (optional)
•Limiting Syslog Messages Sent to the History Table and to SNMP, page 31-10 (optional)
•Enabling the Configuration-Change Logger, page31-11 (optional)
•Configuring UNIX Syslog Servers, page31-12 (optional)

System Log Message Format

System log messages can contain up to 80 characters and a percent sign (%), which follows the optional
sequence number or time-stamp information, if configured. Messages appear in this format:
seq no:timestamp: %facility-severity-MNEMONIC:description (hostname-n)
The part of the message preceding the percent sign depends on the setting of the service
sequence-numbers, service timestamps log datetime, service timestamps log datetime [localtime]
[msec] [show-timezone], or service timestamps log uptime global configuration command.